#!/usr/bin/env python3

# Copyright (c) 2020-2025 Fpemud <fpemud@sina.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.


import os
import abc
import subprocess
from .._handy import Unit
from .._errors import CfgError


class Service(Unit):

    # we don't adhere to systemd's native classification scheme, which is confusing
    #
    # service is an component, that, do concrete things, automatically, in the background
    # service must be configured via one or more files (one or more systemd-units)
    # service must be user-aware, user should be able to enable/disable, start/stop a service
    #
    # for example:
    #   sshd service: composed of sshd.service and ssd.socket, with sshd.service is the main file

    @staticmethod
    @abc.abstractmethod
    def _name2UnitName(name):
        pass

    @staticmethod
    @abc.abstractmethod
    def _create(parent, dir_path, **kwargs):
        pass

    @staticmethod
    @abc.abstractmethod
    def _exists(parent, dir_path, **kwargs):
        # should have same parameters with _create()
        pass

    def is_enabled(self):
        for i, dirPath in enumerate(self._parent._unitDirList):
            for wantedBy in self.wanted_by:
                fullf = os.path.join(dirPath, "%s.wants" % (wantedBy), self._unitName)
                if os.path.islink(fullf):
                    for dirPath2 in self._parent._unitDirList[:i]:
                        if self._unitFile.startswith(dirPath2 + "/"):
                            # example: "/etc/systemd/system/s.service" is invalid if "/usr/lib/systemd/system/swap.target.wants/s.service" exists
                            raise CfgError('"%s" is invalid' % (fullf))
                    if os.readlink(fullf) != self._unitFile:
                        raise CfgError('"%s" should points to "%s"' % (fullf, self._unitFile))
                    return True
        return False

    def enable(self):
        subprocess.check_call(["systemctl", "enable", self._unitName, "--quiet"])

    def disable(self):
        subprocess.check_call(["systemctl", "disable", self._unitName, "--quiet"])

    def remove_and_dispose(self):
        assert not self.is_enabled()
        super().remove_and_dispose()
